Characteristics of study participants (n=488)
| Characteristic | All participants | Infant Toddler Checklist (ITC) | ||
| Positive | Negative | |||
| N | 488 | 46 | 442 | |
| Child and family characteristics | n | |||
| Female sex | 488 | 223 (45.7) | 19 (41.3) | 204 (46.2) |
| Birth weight, kg | 456 | 3.2 (0.6) | 3.1 (0.6) | 3.3 (0.6) |
| Body mass index, z-score | 484 | 0.13 (1.1) | 0.17 (0.9) | 0.12 (1.1) |
| Only child | 486 | 220 (45.3) | 18 (39.1) | 202 (45.9) |
| Maternal age at birth, years | 452 | 34.4 (4.0) | 34.2 (3.8) | 34.5 (4.0) |
| Maternal ethnicity* | 425 | |||
| European | 286 (67.3) | 22 (55.0) | 264 (68.6) | |
| Non-European | 139 (32.7) | 18 (45.0) | 121 (31.4) | |
| Maternal education | 480 | |||
| High school or less | 24 (5.0) | 2 (4.4) | 22 (5.1) | |
| College/university | 456 (95.0) | 43 (95.6) | 413 (94.9) | |
| Family income ($C) | 480 | |||
| Less than $40 000 | 33 (6.9) | 9 (20.0) | 24 (5.5) | |
| $40 000–$79 999 | 54 (11.3) | 8 (17.8) | 46 (10.6) | |
| $80 000–$149 999 | 164 (34.2) | 13 (28.9) | 151 (34.7) | |
| $150 000+ | 229 (47.7) | 15 (33.3) | 214 (49.2) | |
| Family immigration status | 465 | |||
| Canadian born | 269 (57.9) | 24 (54.6) | 245 (58.2) | |
| Immigrant, industrialised | 60 (12.9) | 2 (4.6) | 58 (13.8) | |
| Immigrant, non-industrialised | 136 (29.3) | 18 (40.9) | 118 (28.0) | |
| Family history of developmental concern† | 356 | 29 (8.2) | 4 (10.8) | 25 (7.8) |
| Baseline | ||||
| Age at baseline, months | 488 | 18.5 (1.1) | 18.3 (0.8) | 18.5 (1.2) |
| Positive ITC screen | 488 | 46 (9.4) | 46 (100) | 0 (0) |
| Concern for speech delay | 488 | 28 (5.7) | 28 (60.9) | 0 (0) |
| Concern for other communication delays | 488 | 30 (6.2) | 30 (65.2) | 0 (0) |
| Follow-up | ||||
| Age at follow-up, months | 488 | 46.6 (10.0) | 47.0 (9.5) | 46.6 (10.0) |
| Developmental diagnosis | 488 | 26 (5.3) | 8 (17.4) | 18 (4.1) |
Data regarding baseline characteristics are presented as mean (SD) or N (%).
*Non-European consists of 37 mixed=2 or more ethnic groups (8.2%), 33 South Asian (6.8%), 31 East Asian (6.4%), 14 African and Caribbean (2.9%), 13 Latin American (2.7%), 7 Southeast Asian (1.4%), 3 West Asian/North African (0.6%), 1 Indigenous (0.2%).
†Family history of developmental concerns includes history of ASD, ADHD, or learning disability in mother, father or siblings.
ADHD, attention deficit hyperactivity disorder; ASD, autism spectrum disorder.